Avoiding Feedback

Acoustic feedback can be a problem in any sound system. Audio systems that include wireless microphones are somewhat more prone to feedback than those using only wired microphones, simply because the freedom of movement with wireless makes it more likely that the user will walk in front of the speakers. In addition, omnidirectional microphones are often used with wireless, and they do not provide the same protection from feedback offered by the more familiar directional vocal microphones.

  • Take steps to make it less likely that the wireless user will walk in front of the speakers. These steps can include more rehearsal time, markings on the floor, relocation of the speakers and several other options.

  • Lower the sound level of the speakers nearest the wireless user and increase the level of other speakers to compensate. If possible, rotate the nearest speakers to point them slightly away from the wireless user.

  • Move the microphone closer to the user's lips and lower the transmitter audio gain. This will hold the user's voice at the same level in the sound system while reducing the gain that causes feedback.

  • If feedback results from using a body-pack transmitter and an omnidirectional lavalier microphone, change to a directional microphone.

  • Try changing to a different type of microphone or microphone capsule. Different microphones vary in characteristics and one particular model might be less prone to feedback in a specific situation.

  • Make certain that the transmitter gain is set appropriately for your application. In high-SPL situations, if the transmitter gain is set too high, it may cause overloading of the wireless circuits and increase the chances of feedback.

  • Most standard techniques for reducing feedback will also work with wireless microphones. Because of the increased chance of feedback with wireless, understanding and being able to apply these techniques will be helpful.

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